package org.jeecg.config.SqlFilter;

import org.springframework.context.annotation.Configuration;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
import java.util.Enumeration;

/**
 * @Auther: GMY
 * @Date: 2022/09/15/14:13
 * @Description: sql防注入过滤器
 */
@WebFilter(urlPatterns = "/*",filterName = "sqlFilter")
@Configuration
public class SqlFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }


    /**
     * @param servletRequest
     * @param servletResponse
     * @param filterChain
     * @return void
     * @author GMY
     * @date 2022/9/15 14:17
     * @description sql注入过滤
     */
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        ServletRequest request = servletRequest;
        ServletResponse response = servletResponse;
        // 如果sql防注入关闭，则不执行后续校验操作
        if(!SqlFilterConfigUtils.getOpenSqlProtect()) {
            filterChain.doFilter(request,response);
        } else {
            // 获得所有请求参数名
            Enumeration<String> names = request.getParameterNames();
            String sql = "";
            while (names.hasMoreElements()){
                // 得到参数名
                String name = names.nextElement().toString();
                // 得到参数对应值
                String[] values = request.getParameterValues(name);
                for (int i = 0; i < values.length; i++) {
                    sql += values[i];
                }
            }
            if (sqlValidate(sql)) {
                throw new IOException("您发送请求中的参数中含有非法字符");
            } else {
                filterChain.doFilter(request,response);
            }
        }
    }

    /**
     * @param str
     * @return boolean
     * @author GMY
     * @date 2022/9/15 14:16
     * @description 匹配效验
     */
    protected static boolean sqlValidate(String str){
        // 统一转为小写
        String s = str.toLowerCase();
        // 过滤掉的sql关键字，特殊字符前面需要加\\进行转义
        String badStr =
                "select|select1|select+1|update|and|or|delete|insert|truncate|char|into|substr|ascii|declare|exec|count|master|into|drop|execute|table|"+
                        "char|declare|sitename|xp_cmdshell|like|from|grant|use|group_concat|column_name|" +
                        "information_schema.columns|table_schema|union|where|order|by|" +
                        "'\\*|\\;|\\-|\\--|\\+|\\,|\\//|\\/|\\%|\\#";
        //使用正则表达式进行匹配
        boolean matches = s.matches(badStr);
        return matches;
    }

    @Override
    public void destroy() {

    }
}
